Preoperative anemia in older individuals undergoing major abdominal surgery is associated with early postoperative morbidity: a prospective observational study.

PURPOSE: Preoperative anemia is associated with poor postoperative outcomes. Older patients have limited physiologic reserves, which renders them vulnerable to the stress of major abdominal surgery. We aimed to determine if the severity of preoperative anemia is associated with early postoperative morbidity among older patients undergoing major abdominal surgery. METHODS: Ethics approval was obtained from SingHealth Centralized Institutional Review Board. This is a prospective observational study conducted in the preoperative anesthesia clinic of a tertiary Singapore hospital from 2017 to 2021. Patient demographic data, comorbidities, and intraoperative details were collected. Outcome measures included blood transfusions, complications according to the Postoperative Morbidity Survey, days alive and out of hospital (DaOH), length of hospital stay, and mortality. RESULTS: A total of 469 patients were analyzed, 37.5% of whom had preoperative anemia (serum hemoglobin of < 13 g·dL-1 in males and < 12 g·dL-1 in females). Anemia was significantly associated with older age, a higher age-adjusted Comprehensive Complication Index score, a higher incidence of diabetes mellitus, and a higher proportion of patients with an American Society of Anesthesiologists Physical Status of III or IV. The severity of anemia was associated with the presence of early postoperative morbidity at day 5, increased blood transfusions, longer length of hospital stay, and fewer DaOH at 30 days and six months. CONCLUSION: Anemia is significantly associated with poorer postoperative outcomes in the older population. The impact of anemia on postoperative outcomes could be further evaluated with quality of life indicators, patient-reported outcome measures, and health economic tools.

RéSUMé: OBJECTIF: L'anémie préopératoire est associée à de mauvais devenirs postopératoires. Les patient·es plus âgé·es ont des réserves physiologiques limitées, ce qui les rend vulnérables au stress d'une chirurgie abdominale majeure. Nous avons cherché à déterminer si la gravité de l'anémie préopératoire était associée à une morbidité postopératoire précoce chez les personnes âgées bénéficiant d'une chirurgie abdominale majeure. MéTHODE: L'approbation éthique a été obtenue auprès du Comité d'examen institutionnel centralisé SingHealth. Il s'agit d'une étude observationnelle prospective menée dans la clinique d'anesthésie préopératoire d'un hôpital tertiaire de Singapour de 2017 à 2021. Les données démographiques des patient·es, les comorbidités et les détails peropératoires ont été recueillis. Les critères d'évaluation comprenaient les transfusions sanguines, les complications selon l'Enquête sur la morbidité postopératoire, le nombre de jours de vie hors de l'hôpital, la durée de séjour à l'hôpital et la mortalité. RéSULTATS: Au total, 469 patient·es ont été analysé·es, dont 37,5% présentaient une anémie préopératoire (hémoglobine sérique < 13 g·dL-1 chez les hommes et < 12 g·dL-1 chez les femmes). L'anémie était significativement associée à un âge plus avancé, à un score plus élevé à l'Indice de complication globale ajusté en fonction de l'âge, à une incidence plus élevée de diabète sucré et à une proportion plus élevée de patient·es de statut physique III ou IV selon l'American Society of Anesthesiologists. La sévérité de l'anémie était associée à la présence d'une morbidité postopératoire précoce au jour 5, à une augmentation des transfusions sanguines, à une durée d'hospitalisation plus longue et à une diminution des jours en vie hors hôpital à 30 jours et six mois. CONCLUSION: L'anémie est significativement associée aux moins bons devenirs postopératoires chez les personnes âgées. L'impact de l'anémie sur les devenirs postopératoires pourrait être évalué plus en détail à l'aide d'indicateurs de qualité de vie, de mesures des issues rapportées par les patient·es et d'outils d'économie de la santé.

Cost-savings of short stay sleeve gastrectomy and walk-in hydration clinic versus conventional inpatient care.

OBJECTIVE: We aim to evaluate the cost-saving of the short stay ward (SSW) versus conventional inpatient care following sleeve gastrectomy (LSG). We also compared the readmission rates pre- and post-inception of the intravenous hydration clinic and analyzed the cost-savings. METHODS: Patients who underwent LSG between December 2021 to March 2022 with SSW care were compared with standard inpatient care. Total costs were analyzed using univariate analysis. With a separate cohort of patients, 30-day readmission rates in the 12-months preceding and following implementation of the IV hydration clinic and associated cost-savings were evaluated. RESULTS: After matching on the propensity score to within ± 0.1, 20-subjects pairs were retained. The total cost per SSW-subject was significantly lower at $13,647.81 compared to $15,565.27 for conventional inpatient care (p = 0.0302). Lower average ward charges ($667.76 vs $1371.34, p < 0.0001), lower average daily treatment fee per case ($235.68 vs $836.54, p < 0.0001), and lower average laboratory investigation fee ($612.31 vs $797.21, p < 0.0001) accounted for the difference in costs between the groups. Thirty-day readmission rate reduced from 8.9 to 1.8% after implementation of the hydration clinic (p < 0.01) with decreased 30-day readmission cost (S$96,955.57 vs. S$5910.27, p < 0.01). CONCLUSION: SSW for LSG is cost-effective and should be preferred to inpatient management. Walk-in hydration clinics significantly reduced readmission rates and result in tremendous cost-savings.

AutoScore-Imbalance: An interpretable machine learning tool for development of clinical scores with rare events data.

BACKGROUND: Medical decision-making impacts both individual and public health. Clinical scores are commonly used among various decision-making models to determine the degree of disease deterioration at the bedside. AutoScore was proposed as a useful clinical score generator based on machine learning and a generalized linear model. However, its current framework still leaves room for improvement when addressing unbalanced data of rare events. METHODS: Using machine intelligence approaches, we developed AutoScore-Imbalance, which comprises three components: training dataset optimization, sample weight optimization, and adjusted AutoScore. Baseline techniques for performance comparison included the original AutoScore, full logistic regression, stepwise logistic regression, least absolute shrinkage and selection operator (LASSO), full random forest, and random forest with a reduced number of variables. These models were evaluated based on their area under the curve (AUC) in the receiver operating characteristic analysis and balanced accuracy (i.e., mean value of sensitivity and specificity). By utilizing a publicly accessible dataset from Beth Israel Deaconess Medical Center, we assessed the proposed model and baseline approaches to predict inpatient mortality. RESULTS: AutoScore-Imbalance outperformed baselines in terms of AUC and balanced accuracy. The nine-variable AutoScore-Imbalance sub-model achieved the highest AUC of 0.786 (0.732-0.839), while the eleven-variable original AutoScore obtained an AUC of 0.723 (0.663-0.783), and the logistic regression with 21 variables obtained an AUC of 0.743 (0.685-0.801). The AutoScore-Imbalance sub-model (using a down-sampling algorithm) yielded an AUC of 0.771 (0.718-0.823) with only five variables, demonstrating a good balance between performance and variable sparsity. Furthermore, AutoScore-Imbalance obtained the highest balanced accuracy of 0.757 (0.702-0.805), compared to 0.698 (0.643-0.753) by the original AutoScore and the maximum of 0.720 (0.664-0.769) by other baseline models. CONCLUSIONS: We have developed an interpretable tool to handle clinical data imbalance, presented its structure, and demonstrated its superiority over baselines. The AutoScore-Imbalance tool can be applied to highly unbalanced datasets to gain further insight into rare medical events and facilitate real-world clinical decision-making.

Prevalence and risk factors of preoperative malnutrition risk in older patients and its impact on surgical outcomes: a retrospective observational study.

PURPOSE: Elderly patients are vulnerable to malnutrition and we have started systematic screening for preoperative malnutrition risk in our institution. This study aims to determine the prevalence and risk factors of preoperative malnutrition risk among elderly surgical patients, and its impact on surgical outcomes. METHODS: In this retrospective cohort study of patients ≥ 65 yr old undergoing elective surgery, we recorded demographics, medications, preoperative effort tolerance, Malnutrition Universal Screening Tool (MUST) score, American Society of Anesthesiologists physical status (ASA), Charlson Comorbidity Index (CCI), and Edmonton Frailty Score (EFS). Postoperative complications based on the Clavien-Dindo (CD) classification and hospital length of stay (LOS) were also recorded. RESULTS: Of the 1,033 patients studied, 123 (11.9%) were at risk of malnutrition (MUST ≥ 1), with 48 (4.6%) at high risk (MUST ≥ 2). Unadjusted predictors for high malnutrition risk included ASA ≥ III, higher EFS, higher CCI, polypharmacy (≥ ten medications), poor effort tolerance (metabolic equivalent of tasks < 3), malignancy, general surgery patients, and lower hemoglobin. These patients had higher odds of CD grade ≥ 1 complications compared with those without risk (adjusted odds ratio, 2.30; 95% confidence interval [CI], 1.11 to 4.78; P = 0.025) and 22% longer hospital LOS (adjusted incidence rate ratio,1.22; 95% CI, 1.00 to 1.49; P = 0.049) after multivariate adjustment for sex, severity of surgery, comorbidities, frailty, malignancy, and anemia. CONCLUSION: Preoperative malnutrition risk is prevalent among the elderly. Patients at high malnutrition risk have increased risk of postoperative complications and longer hospital LOS. Patients with high comorbidity burden and frailty should be screened for malnutrition so that nutritional optimization can be sought.

RéSUMé: OBJECTIF: Les patients âgés sont vulnérables à la malnutrition, c'est pourquoi nous avons commencé un dépistage systématique du risque de malnutrition préopératoire dans notre établissement. Cette étude vise à déterminer la prévalence et les facteurs de risque du risque de la malnutrition préopératoire chez les patients chirurgicaux âgés, ainsi que l'impact de la malnutrition sur les devenirs chirurgicaux. MéTHODE: Dans cette étude de cohorte rétrospective portant sur des patients âgés de ≥ 65 ans subissant une chirurgie non urgente, nous avons enregistré les données démographiques, les médicaments, la tolérance préopératoire à l'effort, le score sur l'Outil de dépistage universel de la malnutrition (MUST), le statut physique selon l'American Society of Anesthesiologists (ASA), l'indice de comorbidité de Charlson (ICC) et le score sur l'Échelle de fragilité d'Edmonton (EFS). Les complications postopératoires basées sur la classification de Clavien-Dindo (CD) et la durée de séjour à l'hôpital ont également été enregistrées. RéSULTATS: Parmi les 1033 patients étudiés, 123 (11,9 %) étaient à risque de malnutrition (MUST ≥ 1), et 48 (4,6 %) à haut risque (MUST ≥ 2). Les prédicteurs non ajustés d'un risque élevé de malnutrition comprenaient un statut ASA ≥ III, un score plus élevé à l'EFS, un ICC plus élevé, la polypharmacie (≥ dix médicaments), une tolérance faible à l'effort (équivalent métabolique des tâches < 3), la malignité, les patients de chirurgie générale, et un taux d'hémoglobine plus bas. Ces patients couraient un risque plus élevé de complications de catégorie CD ≥ 1 comparés aux patients sans risque (rapport de cotes ajusté, 2,30; intervalle de confiance [IC] 95 %, 1,11 à 4,78; P = 0,025) et des durées de séjour hospitalier 22 % plus longues (taux d'incidence ajusté,1,22; IC 95 %, 1,00 à 1,49; P = 0,049) après ajustement multivarié pour tenir compte du sexe, de la sévérité de la chirurgie, des comorbidités, de la fragilité, de la malignité et de l'anémie. CONCLUSION: Le risque de malnutrition préopératoire est répandu chez les personnes âgées. Les patients présentant un risque élevé de malnutrition courent un risque accru de complications postopératoires et d'hospitalisation prolongée. Les patients présentant un fardeau de comorbidité et de fragilité élevé devraient être dépistés pour la malnutrition afin de pouvoir optimiser leur nutrition.

Utilizing Machine Learning Methods for Preoperative Prediction of Postsurgical Mortality and Intensive Care Unit Admission.

OBJECTIVE: To compare the performance of machine learning models against the traditionally derived Combined Assessment of Risk Encountered in Surgery (CARES) model and the American Society of Anaesthesiologists-Physical Status (ASA-PS) in the prediction of 30-day postsurgical mortality and need for intensive care unit (ICU) stay >24 hours. BACKGROUND: Prediction of surgical risk preoperatively is important for clinical shared decision-making and planning of health resources such as ICU beds. The current growth of electronic medical records coupled with machine learning presents an opportunity to improve the performance of established risk models. METHODS: All patients aged 18 years and above who underwent noncardiac and nonneurological surgery at Singapore General Hospital (SGH) between 1 January 2012 and 31 October 2016 were included. Patient demographics, comorbidities, preoperative laboratory results, and surgery details were obtained from their electronic medical records. Seventy percent of the observations were randomly selected for training, leaving 30% for testing. Baseline models were CARES and ASA-PS. Candidate models were trained using random forest, adaptive boosting, gradient boosting, and support vector machine. Models were evaluated on area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC). RESULTS: A total of 90,785 patients were included, of whom 539 (0.6%) died within 30 days and 1264 (1.4%) required ICU admission >24 hours postoperatively. Baseline models achieved high AUROCs despite poor sensitivities by predicting all negative in a predominantly negative dataset. Gradient boosting was the best performing model with AUPRCs of 0.23 and 0.38 for mortality and ICU admission outcomes respectively. CONCLUSIONS: Machine learning can be used to improve surgical risk prediction compared to traditional risk calculators. AUPRC should be used to evaluate model predictive performance instead of AUROC when the dataset is imbalanced.

Coronavirus disease 2019 (COVID-19): an evidence map of medical literature.

BACKGROUND: Since the beginning of the COVID-19 outbreak in December 2019, a substantial body of COVID-19 medical literature has been generated. As of June 2020, gaps and longitudinal trends in the COVID-19 medical literature remain unidentified, despite potential benefits for research prioritisation and policy setting in both the COVID-19 pandemic and future large-scale public health crises. METHODS: In this paper, we searched PubMed and Embase for medical literature on COVID-19 between 1 January and 24 March 2020. We characterised the growth of the early COVID-19 medical literature using evidence maps and bibliometric analyses to elicit cross-sectional and longitudinal trends and systematically identify gaps. RESULTS: The early COVID-19 medical literature originated primarily from Asia and focused mainly on clinical features and diagnosis of the disease. Many areas of potential research remain underexplored, such as mental health, the use of novel technologies and artificial intelligence, pathophysiology of COVID-19 within different body systems, and indirect effects of COVID-19 on the care of non-COVID-19 patients. Few articles involved research collaboration at the international level (24.7%). The median submission-to-publication duration was 8 days (interquartile range: 4-16). CONCLUSIONS: Although in its early phase, COVID-19 research has generated a large volume of publications. However, there are still knowledge gaps yet to be filled and areas for improvement for the global research community. Our analysis of early COVID-19 research may be valuable in informing research prioritisation and policy planning both in the current COVID-19 pandemic and similar global health crises.

Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement on Perioperative Smoking Cessation.

Smokers are at increased risk for surgical complications. Despite the known benefits of smoking cessation, many perioperative health care providers do not routinely provide smoking cessation interventions. The variation in delivery of perioperative smoking cessation interventions may be due to limited high-level evidence for whether smoking cessation interventions used in the general population are effective and feasible in the surgical population, as well as the challenges and barriers to implementation of interventions. Yet smoking is a potentially modifiable risk factor for improving short- and long-term patient outcomes. The purpose of the Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement on Perioperative Smoking Cessation is to present recommendations based on current scientific evidence in surgical patients. These statements address questions regarding the timing and intensity of interventions, roles of perioperative health care providers, and behavioral and pharmacological interventions. Barriers and strategies to overcome challenges surrounding implementation of interventions and future areas of research are identified. These statements are based on the current state of knowledge and its interpretation by a multidisciplinary group of experts at the time of publication.

Association between preoperative anaemia and blood transfusion with long-term functional and quality of life outcomes amongst patients undergoing primary total knee arthroplasty in Singapore: a single-centre retrospective study.

PURPOSE: Preoperative anaemia affects up to one-third of patients undergoing total knee arthroplasty (TKA) and is associated with increased blood transfusion and prolonged hospitalisation. Prior studies have associated preoperative anaemia with poorer functional recovery after total hip arthroplasty. However, the association between preoperative anaemia and functional outcomes following TKA is unknown. We aim to determine whether preoperative anaemia and perioperative blood transfusion affect health-related quality of life (HRQoL) and functional outcomes following TKA. METHODS: Retrospective analysis of 1994 patients who underwent primary unilateral TKA from 2013 to 2014 was performed. Anaemia was defined according to the World Health Organisation definition. Baseline and 6-month postoperative HRQoL was assessed with the 36-Item Short Form Survey (SF-36), while function was assessed with Oxford Knee Score (OKS) and Knee Society Function Score (KSFS). Physical function (PF), role physical (RP), bodily pain (BP), social function (SF) and role emotional (RE) domains of SF-36, OKS and KSFS demonstrated significant change greater than the minimal clinically important difference between baseline and 6 months. Analysis of covariance (ANCOVA) was performed to identify predictors of 6-month scores. RESULTS: The incidence of preoperative anaemia was 22.3%. 4.3% of patients received blood transfusions. Preoperative anaemia and perioperative blood transfusion did not significantly affect SF-36, KSFS and OKS scores at 6 months postoperatively. Poor baseline SF-36, KSS and OKS scores and high BMI ≥ 37.5 kg/m2 are consistently associated with lower scores at 6 months. CONCLUSION: Preoperative anaemia and perioperative blood transfusion did not significantly affect HRQoL and functional outcomes following primary TKA. Poor baseline and obesity were associated with poorer outcomes.

Diagnosis and treatment of obstructive sleep apnea during pregnancy.

PURPOSE OF REVIEW: This review aims to provide an update on recent advances in the diagnosis and treatment of obstructive sleep apnea (OSA) during pregnancy and its effect on maternal and fetal outcomes. RECENT FINDINGS: Current OSA screening tools may not perform well in this population. There are some pieces of evidence linking poorer maternal and neonatal outcome with pregnant patients having OSA. At present, there are inadequate data on which to base fetal or maternal parameters for treatment of OSA, and no evidence that treatment in the short-term impacts maternal or neonatal outcomes. SUMMARY: Further research is needed to help in the detection and treatment of OSA in pregnancy.

Perioperative management for the obese outpatient.

PURPOSE OF REVIEW: Incidence of obesity continues to rise and ambulatory surgical centers will need to be prepared for the increase in the obese surgical patients. This review aims to provide recent updates in managing the obese patients in an ambulatory surgical center and to address key clinical questions, such as patient selection, assessment and optimization, as well as important perioperative consideration. RECENT FINDINGS: With low rate of major intraoperative adverse events, obesity has not been associated with unplanned admission after day surgical procedures. There is, however, a higher rate of perioperative adverse events in the super-obese patients. Recent developments in patient assessment include validation of STOP-Bang questionnaire for obstructive sleep apnea in the obese population. Nevertheless, patients with obesity hypoventilation syndrome should be identified and optimized as they are more prone to develop adverse events. The obese patients are also at a higher risk of difficult airway, and recommendations for the airway management are available. SUMMARY: With extra considerations and meticulous perioperative management, it is well tolerated to accept obese patients for ambulatory surgery. The super-obese patients, however, are at a higher risk for perioperative adverse events.

The SingHealth Perioperative and Anesthesia Subject Area Registry (PASAR), a large-scale perioperative data mart and registry.

BACKGROUND: To enhance perioperative outcomes, a perioperative registry that integrates high-quality real-world data throughout the perioperative period is essential. Singapore General Hospital established the Perioperative and Anesthesia Subject Area Registry (PASAR) to unify data from the preoperative, intraoperative, and postoperative stages. This study presents the methodology employed to create this database. METHODS: Since 2016, data from surgical patients have been collected from the hospital electronic medical record systems, de-identified, and stored securely in compliance with privacy and data protection laws. As a representative sample, data from initiation in 2016 to December 2022 were collected. RESULTS: As of December 2022, PASAR data comprise 26 tables, encompassing 153,312 patient admissions and 168,977 operation sessions. For this period, the median age of the patients was 60.0 years, sex distribution was balanced, and the majority were Chinese. Hypertension and cardiovascular comorbidities were also prevalent. Information including operation type and time, intensive care unit (ICU) length of stay, and 30-day and 1-year mortality rates were collected. Emergency surgeries resulted in longer ICU stays, but shorter operation times than elective surgeries. CONCLUSIONS: The PASAR provides a comprehensive and automated approach to gathering high-quality perioperative patient data.

A comparison between the Bonfils Intubation Fiberscope and McCoy laryngoscope for tracheal intubation in patients with a simulated difficult airway.

BACKGROUND: The Bonfils Intubation Fibrescope (Bonfils) and the McCoy laryngoscope (McCoy) are airway devices designed to assist tracheal intubation in difficult cases. Individually, both the Bonfils and McCoy have demonstrated superiority to the Macintosh laryngoscope in a simulated difficult airway. In this study, we compared the Bonfils with the McCoy laryngoscope in patients whose tracheal intubation had been intentionally hindered. Our primary hypothesis was that there is a significant difference in the rate of success for tracheal intubation when using the Bonfils or McCoy laryngoscope in patients with an intentionally hindered airway. METHODS: Patients undergoing elective surgery and requiring general anesthesia and endotracheal intubation were randomized to have intubation performed with either the Bonfils or McCoy laryngoscope. All patients were fitted with a hard cervical collar to simulate a difficult airway. Data collected included the success rate of endotracheal intubation, the time taken for intubation, the number of attempts required, the use of further aids to intubation, hemodynamic variables, and the incidence of adverse events. The primary end point was the relative rate of successful tracheal intubation. Categorical outcome measures were compared using the χ test, or Fisher exact test where appropriate, and the Mann-Whitney U test or unpaired Student t test where data were continuous. For the nonnormally distributed data, log transformation was adopted, and t test was performed if normalcy was achieved. RESULTS: Sixty adult patients were recruited and randomized into 2 groups of 30 patients each. There was no difference in the rate of successful intubation between groups (95% confidence interval [CI], -11.6% to 11.6%), with a 100% success rate achieved in both groups. We found no statistically significant differences between groups in the time taken for intubation (P = 0.32, 95% CI, 0.90-1.41) and percentage of single attempts (P = 0.47, 95% CI, -30.3% to 9.7%). However, further aids to intubation were required more frequently when using the McCoy laryngoscope (P < 0.001, 95% CI, 0.17-0.46), with 18 patients in the McCoy group requiring the use of an elastic bougie, and no patients in the Bonfils group requiring any aids. There were no significant differences found in the rates of adverse events. CONCLUSIONS: In the hands of trained operators, there appears to be no clinically significant difference in success, time to intubation, or adverse outcomes, when comparing the Bonfils with the McCoy laryngoscope, in the setting of a simulated difficult airway. The choice to use either device should remain based on appropriate patient selection, available aids, individual operator's experience, and economic circumstances.

Improving the accuracy of revised cardiac risk index with HbA1C: Hemoglobin ratio (HH ratio) - A retrospective cohort study.

Background: The current Lee's Revised cardiac risk index (RCRI) was created in 1999. Validation studies have found RCRI to be only moderately discriminant. The "Diabetes Mellitus on insulin" component of the score does not accurately reflect the severity of the disease. A previously studied HbA1C:Hemoglobin ratio shows an improved association with outcomes than individual components alone. Study design: A retrospective cohort study was performed in diabetic patients undergoing non-cardiac surgery. Ethics approval was obtained. The study compares the predictive value of RCRI and substitution of the "DM on insulin" component with HH ratio for 30- and 90-day mortality, and postoperative acute myocardial injury (AMI) and acute kidney injury (AKI). Results: A total of 20,099 adult patients were included in the final analysis. The incidence of 30- and 90-day mortality was at 4.2 and 6.5%, respectively. Substitution of HH ratio in RCRI resulted in 687 more patients being in the moderate to high-risk category. The substituted HH-RCRI score had better prediction for 30-day (AUC 0.66 vs. 0.69, p < 0.001) and 90-day mortality (AUC 0.67 vs. 0.70, p < 0.001), and postoperative AMI (AUC 0.69 vs. 0.71, p < 0.001) and AKI (AUC 0.57 vs. 0.62, p < 0.001). Conclusion: Although currently not an universal practice, substitution of "DM on insulin" with HbA1C:Hemoglobin ratio in RCRI score improves the accuracy of the RCRI risk prediction model in diabetic patients going for non-cardiac surgery.

Transforming the perioperative medicine care model: The Singapore experience.

More than 300 million surgeries are performed worldwide annually. Established perioperative centres in the UK, USA and Australia have demonstrated the impact of improving perioperative care in reducing costs, increasing patient satisfaction and improving population health. Likewise, the surgical burden of care in Asia is increasing, but with sociocultural, economic and epigenetic differences compared to the west. As Singapore's largest hospital, the Singapore General Hospital pre-admission perioperative clinic sees about 20,000 patients annually. We aim to illustrate Singapore General Hospital's perioperative model of care to contribute to the paucity of literature describing perioperative programme implementation within Asia, and to encourage the cross-sharing of perioperative practices internationally. Our perioperative framework navigates risk assessment, risk counselling, and mitigation of health, medical and functional risks to better patients' perioperative outcomes and population health. We have implemented evidence-based pathways for common conditions such as anaemia and malnutrition, including a multidisciplinary programme for the elderly to tackle frailty and reduce length of stay. We describe how we have enhanced local risk profiling with the Combined Assessment of Risk Encountered in Surgery surgical risk calculator derived locally using a gradient boosting machine learning model. Finally, we report clinical outcomes of these interventions and discuss further challenges and new initiatives at each tier of our perioperative model. Our perioperative care model provides a framework that other centres can adopt to promote value-driven care, while catering for differences in the Asian population, thereby promoting evidence-based improvements in the area of perioperative medicine.

Preoperative shock index in major abdominal emergency surgery.

Introduction: Major abdominal emergency surgery (MAES) patients have a high risk of mortality and complications. The time-sensitive nature of MAES necessitates an easily calculable risk-scoring tool. Shock index (SI) is obtained by dividing heart rate (HR) by systolic blood pressure (SBP) and provides insight into a patient's haemodynamic status. We aimed to evaluate SI's usefulness in predicting postoperative mortality, acute kidney injury (AKI), requirements for intensive care unit (ICU) and high-dependency monitoring, and the ICU length of stay (LOS). Method: We retrospectively reviewed 212,089 MAES patients from January 2013 to December 2020. The cohort was propensity matched, and 3960 patients were included. The first HR and SBP recorded in the anaesthesia chart were used to calculate SI. Regression models were used to investigate the association between SI and outcomes. The relationship between SI and survival was explored with Kaplan-Meier curves. Results: There were significant associations between SI and mortality at 1 month (odds ratio [OR] 2.40 [1.67-3.39], P<0.001), 3 months (OR 2.13 [1.56-2.88], P<0.001), and at 2 years (OR 1.77 [1.38-2.25], P<0.001). Multivariate analysis revealed significant relationships between SI and mortality at 1 month (OR 3.51 [1.20-10.3], P=0.021) and at 3 months (OR 3.05 [1.07-8.54], P=0.034). Univariate and multivariate analysis also revealed significant relationships between SI and AKI (P<0.001), postoperative ICU admission (P<0.005) and ICU LOS (P<0.001). SI does not significantly affect 2-year mortality. Conclusion: SI is useful in predicting postopera-tive mortality at 1 month, 3 months, AKI, postoperative ICU admission and ICU LOS.

Prehabilitation programs - a systematic review of the economic evidence.

Introduction: Prehabilitation, which involves improving a patient's physical and psychological condition before surgery, has shown potential benefits but has yet to be extensively studied from an economic perspective. To address this gap, a systematic review was conducted to summarize existing economic evaluations of prehabilitation interventions. Methods: The PRISMA Protocols 2015 checklist was followed. Over 16,000 manuscripts were reviewed, and 99 reports on preoperative interventions and screening tests were identified, of which 12 studies were included in this analysis. The costs are expressed in Pounds (GBP, £) and adjusted for inflation to December 2022. Results: The studies were conducted in Western countries, focusing on specific surgical subspecialties. While the interventions and study designs varied, most studies demonstrated cost savings in the intervention group compared to the control group. Additionally, all cost-effectiveness analysis studies favored the intervention group. However, the review also identified several limitations. Many studies had a moderate or high risk of bias, and critical information such as time horizons and discount rates were often missing. Important components like heterogeneity, distributional effects, and uncertainty were frequently lacking as well. The misclassification of economic evaluation types highlighted a lack of knowledge among physicians in prehabilitation research. Conclusion: This review reveals a lack of robust evidence regarding the economics of prehabilitation programs for surgical patients. This suggests a need for further research with rigorous methods and accurate definitions.

Discordant American Society of Anesthesiologists Physical Status Classification between anesthesiologists and surgeons and its correlation with adverse patient outcomes.

The American Society of Anesthesiologists Physical Status Classification (ASA) is used for communication of patient health status, risk scoring, benchmarking and financial claims. Prior studies using hypothetical scenarios have shown poor concordance of ASA classification among healthcare providers. There is a paucity of studies using clinical data, and of clinical factors or patient outcomes associated with discordant classification. The study aims to assess ASA classification concordance between surgeons and anesthesiologists, factors surrounding discordance and its impact on patient outcomes. This retrospective cohort study was conducted in a tertiary medical center on 46,284 consecutive patients undergoing elective surgery between January 2017 and December 2019. The ASA class showed moderate concordance (weighted Cohen's κ 0.53) between surgeons and anesthesiologists. We found significant associations between discordant classification and patient comorbidities, age and race. Patients with discordant classification had a higher risk of 30-day mortality (odds ratio (OR) 2.00, 95% confidence interval (CI) = 1.52-2.62, p < 0.0001), 1-year mortality (OR 1.53, 95% CI = 1.38-1.69, p < 0.0001), and Intensive Care Unit admission > 24 h (OR 1.69, 95% CI = 1.47-1.94, p < 0.0001). Hence, there is a need for improved standardization of ASA scoring and cross-specialty review in ASA-discordant cases.

Outcomes after natural orifice extraction vs conventional specimen extraction surgery for colorectal cancer: A propensity score-matched analysis.

BACKGROUND: Natural orifice specimen extraction (NOSE) via the anus or vagina replaces conventional transabdominal specimen retrieval via the transabdominal route through a limited mid-line laparotomy or Pfannenstiel incision. Reducing the number of laparoscopic ports further decreases operative abdominal wall trauma. These techniques reduce the surgical wound size as well as the risk of incision-related morbidity. AIM: To compare short-term outcomes following 3-port NOSE surgery with a matched cohort of conventional non-NOSE colorectal cancer surgery. METHODS: Patients who underwent elective 3-port laparoscopic colorectal NOSE surgery between February to October 2021 were identified. Selection criteria for NOSE surgery was adapted from the 2019 International Consensus on Natural Orifice Specimen Extraction Surgery for colorectal cancer. Patients with clinical T4 or N2 tumors on staging computed tomography were also excluded. The propensity score-matched cohort was identified amongst patients who underwent conventional laparoscopic colorectal surgery from January 2019 to December 2020. Matching was performed in the ratio of 1:4 based on age, gender, type of resection, and p - tumor node metastasis staging. RESULTS: Over the eight-month study duration, 14 consecutive cases (nine female, five male) of elective 3-port laparoscopic surgery with NOSE were performed for colorectal cancer. Median age and body mass index were 70 (range 43-82) years and 24.1 (range 20.0-31.7) kg/m2 respectively. Six patients underwent transanal NOSE and eight had transvaginal NOSE. Median operative time, intraoperative blood loss and postoperative length of stay were 208 (range 165-365) min, 30 (range 10-150) mL and 3 (range 2-6) d respectively. Two (14%) suffered minor postoperative compilations not attributable to the NOSE procedure. Median follow-up duration was 12 (range 8-15) mo. No instances of mortality, local or distant disease recurrence were recorded in this cohort. Compared to the conventional surgery cohort of 56 patients, the 3-port NOSE cohort had significantly quicker mean return of bowel function (2.6 vs 1.2 d, P < 0.001), reduced postoperative pain and patient-controlled analgesia use, and decreased length of hospital stay (6.4 vs 3.4 d, P < 0.001). There were no statistical differences in surgical duration and perioperative complication rates between the NOSE and non-NOSE cohorts. CONCLUSION: 3-port laparoscopic colorectal surgery with NOSE is a feasible technique, augmenting the minimally invasive nature of surgery and producing good outcomes. Appropriate patient selection and expertise in conventional laparoscopy are required.